The bitter politics of envy. Who would have guessed that the most memorable phrase of the 2012 primary season would come from the almost deliberately bland Mitt Romney? But that line, inserted in his New Hampshire primary victory speech, could turn out to be the worst miscalculation of his career.

At the moment Romney uttered those words, he was on the top of the political world. There seemed to be no doubt about his winning the Republican nomination for president. Such a solid, sweeping victory as he achieved in New Hampshire called for a show of generosity toward his rivals, and a simple restatement of his case against President Obama — the type of speech that Romney, in preserving his front-runner aura, has been delivering with numbing regularity all fall and winter.

But Romney’s campaign apparently felt the need to scold his rivals for dwelling on his career at Bain Capital. Rather than ignore the attacks, or offer a thoughtful response akin to what Obama did after the controversy about Rev. Jeremiah Wright, Romney tried to squash the criticism with arrogance.

“President Obama wants to put free enterprise on trial,” Romney said, reading from a teleprompter. “In the last few days, we have seen some desperate Republicans join forces with him. This is such a mistake for our party and for our nation. This country already has a leader who divides us with the bitter politics of envy.”

Here’s what Romney and his aides were probably thinking: They knew that Newt Gingrich was going to hang around and torment Romney, focusing on Bain Capital. They wanted to make the point, at a peak moment of victory, that Gingrich’s attacks would only play into Obama’s hands — that only Democrats could benefit from this internal blood-letting. Gingrich bore all the marks of poor-loserdom — he was the original spoilsport, unpopular with his colleagues — and Romney was hoping to get GOP leaders to help shut Gingrich down.

If that’s what he wanted, Romney should have simply condemned all the negativity — claiming that the viciousness of the primaries was hurting the party — without getting into specific lines of attack. That would have allowed Romney to sound statesmanlike — above the fray, looking out for the best interests of the GOP as its all-but-crowned leader. Instead, Romney not only made the self-righteous claim that attacks on his business career were attacks on the free-enterprise system, but he suggested that those making the attacks were merely envious of him.

Standing on the podium with his beautiful wife, five loving children, and carpet of neatly turned out grandchildren, Romney might well have been a subject of envy — but it hardly suited him to say so. He seemed to be saying, “Don’t hate me for my perfect life.”

But questions about Romney’s stewardship of Bain Capital are serious, and totally within the bounds of normal campaigning. Moreover, Romney seems to have underestimated the extent to which Tea Party voters have gravitated toward the Republicans because they saw the GOP (wrongly, perhaps) as the party opposed to Wall Street. When these voters think of free enterprise, they think of the corner market down the street, not private-equity firms.

Romney’s words were like waving a red flag in front of the one bull who could gore him — not Gingrich, but the Tea Party. And his insistence that only Democrats would stoop to question his corporate past reflected a profound misreading of today’s Republican Party.

Romney remains the GOP frontrunner, even as polls suggest he might be headed for a smackdown in the South Carolina primary. There’s plenty of time for him to recover. He may even come out inoculated against Bain Capital-related charges in the fall. But he has only himself to blame for putting what looked like a sure thing — his inevitability as the Republican nominee — into jeopardy.

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